In the World of the High Tech Redneck, the Graybeard is the old guy who earned his gray by making all the mistakes, and then tries to keep the young 'uns from repeating them. Silicon Graybeard is my term for an old hardware engineer; a circuit designer. Here are mental droppings from a newly retired radio engineer running from tech news to economics; from firearms to the world at large; from radio to home machine shops and making all kinds of stuff.

Friday, January 3, 2014

SR-71 Blackbird Story

I received the following email today, and went to look up whether or not it's true, or an internet legend. It's an amazing story, and I thought some of you would find it as neat as I did.

SR 71 Blackbird Mach 3.18 Break-up - Bill Weaver, test pilot.

Among professional aviators, there’s a well-worn saying that flying is simply hours of boredom punctuated by moments of sheer terror. But I don’t recall too many periods of boredom during my 30 year period with Lockheed, most of which was as a test pilot.

Jim Zwayer, a Lockheed flight-test specialist, and I were evaluating systems on an SR-71 Blackbird test from Edwards in January, 1966. We also were investigating procedures designed to reduce trim drag and improve high-Mach cruise performance. The latter involved flying with the center-of-gravity (CG) located further aft than normal, reducing the Blackbird's longitudinal stability.

We took off from Edwards at 11:20 a.m. and completed the mission's first leg without incident. After refueling from a KC-135 tanker, we turned eastbound, accelerated to a Mach 3.2-cruise speed and climbed to 78,000 ft., our initial cruise-climb altitude.

Several minutes into cruise, the right engine inlet's automatic control system malfunctioned, requiring a switch to manual control. The SR-71's inlet configuration was automatically adjusted during supersonic flight to decelerate airflow in the duct, slowing it to subsonic speed before reaching the engine's face. This was accomplished by the inlet's center-body spike translating aft, and by modulating the inlet's forward bypass doors.

Normally, these
actions were scheduled automatically as a function of Mach number,
positioning the normal shock wave (where air flow becomes subsonic) inside
the inlet to ensure optimum engine performance. Without proper scheduling,
disturbances inside the inlet could result in the shock wave being expelled
forward - a phenomenon known as an "inlet unstart."

That causes an
instantaneous loss of engine thrust, explosive banging noises and violent
yawing of the aircraft--like being in a train wreck. Unstarts were not
uncommon at that time in the SR-71's development, but a properly functioning
system would recapture the shock wave and restore normal
operation.

On the planned test
profile, we entered a programmed 35-deg. bank turn to the right. An
immediate unstart occurred on the right engine, forcing the aircraft to roll
further right and start to pitch up. I jammed the control stick as far left
and forward as it would go. No response. I instantly knew we were in for a
wild ride. I attempted to tell Jim what was happening and to stay with the
airplane until we reached a lower speed and altitude. I didn't think the
chances of surviving an ejection at Mach 3.18 and 78,800 ft. were very good.
However, g-forces built up so rapidly that my words came out garbled and
unintelligible, as confirmed later by the cockpit voice
recorder.

The cumulative
effects of system malfunctions, reduced longitudinal stability, increased
angle-of-attack in the turn, supersonic speed, high altitude and other
factors imposed forces on the airframe that exceeded flight control
authority and the Stability Augmentation System's ability to restore
control.

Everything seemed to unfold in slow motion. I learned later the
time from event onset to catastrophic departure from controlled flight was
only 2-3 seconds. Still trying to communicate with Jim, I blacked out,
succumbing to extremely high g-forces.

Then the SR-71 literally disintegrated around us. From that point, I was just along for the ride. And
my next recollection was a hazy thought that I was having a bad dream. Maybe
I'll wake up and get out of this mess, I mused. Gradually regaining
consciousness, I realized this was no dream; it had really happened. That
also was disturbing, because I COULD NOT HAVE SURVIVED what had just
happened.

I must be dead.
Since I didn't feel bad - just a detached sense of euphoria. I decided being
dead wasn't so bad after all. As full awareness took hold, I realized I was
not dead. But somehow I had separated from the airplane. I had no idea how
this could have happened. I hadn't initiated an ejection. The sound of
rushing air and what sounded like straps flapping in the wind confirmed I
was falling, but I couldn't see anything. My pressure suit's face plate had
frozen over and I was staring at a layer of ice.

The pressure suit
was inflated, so I knew an emergency oxygen cylinder in the seat kit
attached to my parachute harness was functioning. It not only supplied
breathing oxygen, but also pressurized the suit, preventing my blood from
boiling at extremely high altitudes. I didn't appreciate it at the time, but
the suit's pressurization had also provided physical protection from intense
buffeting and g-forces. That inflated suit had become my own escape
capsule.

My next concern was
about stability and tumbling. Air density at high altitude is insufficient
to resist a body's tumbling motions, and centrifugal forces high enough to
cause physical injury could develop quickly. For that reason, the SR-71's
parachute system was designed to automatically deploy a small-diameter
stabilizing chute shortly after ejection and seat separation. Since I had
not intentionally activated the ejection system, and assuming all automatic
functions depended on a proper ejection sequence, it occurred to me the
stabilizing chute may not have deployed.

However, I quickly
determined I was falling vertically and not tumbling. The little chute must
have deployed and was doing its job. Next concern: the main parachute, which
was designed to open automatically at 15,000 ft. Again I had no assurance
the automatic-opening function would work.

I couldn't ascertain my altitude
because I still couldn't see through the iced-up faceplate. There was no way
to know how long I had been blacked-out or how far I had fallen. I felt for
the manual-activation D-ring on my chute harness, but with the suit inflated
and my hands numbed by cold, I couldn't locate it. I decided I'd better open
the faceplate, try to estimate my height above the ground, then locate that
"D" ring. Just as I reached for the faceplate, I felt the reassuring sudden
deceleration of main-chute deployment.

I raised the frozen faceplate and
discovered its uplatch was broken. Using one hand to hold that plate up, I
saw I was descending through a clear, winter sky with unlimited visibility.
I was greatly relieved to see Jim's parachute coming down about a quarter of
a mile away. I didn't think either of us could have survived the aircraft's
breakup, so seeing Jim had also escaped lifted my spirits incredibly. I
could also see burning wreckage on the ground a few miles from where we
would land. The terrain didn't look at all inviting, a desolate, high
plateau dotted with patches of snow and no signs of habitation.

I tried to rotate
the parachute and look in other directions. But with one hand devoted to
keeping the face plate up and both hands numb from high-altitude,
subfreezing temperatures, I couldn't manipulate the risers enough to turn.
Before the breakup, we'd started a turn in the New
Mexico-Colorado-Oklahoma-Texas border region. The SR-71 had a turning radius
of about 100 mi. at that speed and altitude, so I wasn't even sure what
state we were going to land in. But, because it was about 3:00 p.m., I was
certain we would be spending the night out here.

At about 300 ft.
above the ground, I yanked the seat kit's release handle and made sure it
was still tied to me by a long lanyard. Releasing the heavy kit ensured I
wouldn't land with it attached to my derriere, which could break a leg or
cause other injuries. I then tried to recall what survival items were in
that kit, as well as techniques I had been taught in survival training.
Looking down, I was startled to see a fairly large animal, perhaps an
antelope, directly under me. Evidently, it was just as startled as I was
because it literally took off in a cloud of dust.

My first-ever
parachute landing was pretty smooth. I landed on fairly soft ground,
managing to avoid rocks, cacti and antelopes. My chute was still billowing
in the wind, though. I struggled to collapse it with one hand, holding the
still-frozen faceplate up with the other. "Can I help you?" a
voice said. Was I hearing things? I must be hallucinating. Then I looked up
and saw a guy walking toward me, wearing a cowboy hat. A helicopter was
idling a short distance behind him. If I had been at Edwards and told the
search-and-rescue unit that I was going to bail out over the Rogers Dry Lake
at a particular time of day, a crew couldn't have gotten to me as fast as
that cowboy-pilot had.

The gentleman was Albert Mitchell, Jr., owner of a
huge cattle ranch in northeastern New Mexico . I had landed about 1.5 mi.
from his ranch house, and from a hangar for his two-place Hughes helicopter.
Amazed to see him, I replied I was having a little trouble with my chute. He
walked over and collapsed the canopy, anchoring it with several rocks. He
had seen Jim and me floating down and had radioed the New Mexico Highway
Patrol, the Air Force, and the nearest hospital.

Extracting myself
from the parachute harness, I discovered the source of those flapping-strap
noises heard on the way down. My seat belt and shoulder harness were still
draped around me, attached and latched. The lap belt had been shredded on
each side of my hips, where the straps had fed through knurled adjustment
rollers. The shoulder harness had shredded in a similar manner across my
back. The ejection seat had never left the airplane. I had been ripped out
of it by the extreme forces, with the seat belt and shoulder harness still
fastened.<

I also noted that
one of the two lines that supplied oxygen to my pressure suit had come
loose, and the other was barely hanging on. If that second line had become
detached at high altitude, the deflated pressure suit wouldn't have provided
any protection. I knew an oxygen supply was critical for breathing and
suit-pressurization, but didn't appreciate how much physical protection an
inflated pressure suit could provide.

That the suit could withstand forces
sufficient to disintegrate an airplane and shred heavy nylon seat belts, yet
leave me with only a few bruises and minor whiplash was impressive. I truly
appreciated having my own little escape capsule.

After helping me with the chute, Mitchell said he'd check on Jim. He climbed into his
helicopter, flew a short distance away and returned about 10 minutes later
with devastating news: Jim was dead. Apparently, he had suffered a broken
neck during the aircraft's disintegration and was killed instantly. Mitchell
said his ranch foreman would soon arrive to watch over Jim's body until the
authorities arrived. I asked to see Jim and, after verifying there was
nothing more that could be done, agreed to let Mitchell fly me to the
Tucumcari hospital, about 60 mi. to the south.

I have vivid memories of that helicopter flight, as well. I didn't know much about
rotorcraft, but I knew a lot about "red lines," and Mitchell kept the
airspeed at or above red line all the way. The little helicopter vibrated
and shook a lot more than I thought it should have. I tried to reassure the
cowboy-pilot I was feeling OK; there was no need to rush. But since he'd
notified the hospital staff that we were inbound, he insisted we get there
as soon as possible. I couldn't help but think how ironic it would be to
have survived one disaster only to be done in by the helicopter that had
come to my rescue.

However, we made it
to the hospital safely - and quickly. Soon, I was able to contact Lockheed's
flight test office at Edwards. The test team there had been notified
initially about the loss of radio and radar contact, then told the aircraft
had been lost. They also knew what our flight conditions had been at the
time, and assumed no one could have survived. I explained what had happened,
describing in fairly accurate detail the flight conditions prior to
breakup.

The next day, our
flight profile was duplicated on the SR-71 flight simulator at Beale AFB,
Calif. The outcome was identical. Steps were immediately taken to prevent a
recurrence of our accident. Testing at a CG aft of normal limits was
discontinued, and trim-drag issues were subsequently resolved via
aerodynamic means. The inlet control system was continuously improved and,
with subsequent development of the Digital Automatic Flight and Inlet
Control System, inlet unstarts became rare.

Investigation of our accident
revealed that the nose section of the aircraft had broken off aft of the
rear cockpit and crashed about 10 mi. from the main wreckage. Parts were
scattered over an area approximately 15 mi. long and 10 mi. wide. Extremely
high air loads and g-forces, both positive and negative, had literally
ripped Jim and me from the airplane. Unbelievably good luck is the only
explanation for my escaping relatively unscathed from that disintegrating
aircraft.

Two weeks after the
accident, I was back in an SR-71, flying the first sortie on a brand-new
bird at Lockheed's Palmdale , California assembly and test facility. It was
my first flight since the accident, so a flight test engineer in the back
seat was probably a little apprehensive about my state of mind and
confidence. As we roared down the runway and lifted off, I heard an anxious
voice over the intercom.

"Bill! Bill! Are you there?"

"Yeah, George. What's
the matter?"

"Thank God! I thought you might have left."

The rear cockpit of
the SR-71 has no forward visibility - only a small window on each side - and
George couldn't see me. A big red light on the master-warning panel in the
rear cockpit had illuminated just as we rotated, stating: "Pilot Ejected."
Fortunately, the cause was a misadjusted micro switch; not my
departure.

Bill Weaver flight-tested all models of the Mach-2 F-104 Starfighter and the entire
family of Mach 3+ Blackbirds including the A-12, YF-12, and SR-71. He
subsequently was assigned to Lockheed's L-1011 project as an engineering
test pilot, and became the company's chief pilot. He later retired as
Division Manager of Commercial Flying Operations, and continued to fly the
Orbital Sciences Corp.'s L-1011, which was modified to carry the Pegasus
satellite-launch vehicle. And as an FAA Designated Engineering
Representative Flight Test Pilot, was involved in various
aircraft-modification projects, conducting certification flight
tests.<

SR-71A (61-7952 / 2003)

This aircraft disintegrated on 25 January 1966 during a high-speed,
high-altitude test flight when it developed a severe case of engine
unstart.
Lockheed test pilot BillWeaver survived although his ejection seat never left the plane! Reconnaissance System Officer (RSO) Jim Zwayer died in a
high-G bailout. The incident occurred near Tucumcari, New Mexico.

Test pilots are a special breed. One of the most interesting things about reading this story is the calm, rational approach it shows. Realizing he's somehow floating alone in space, somehow no longer in the airplane he was just flying, there's not a trace of anguish; instead, his concentration is laser focused on "what's going on now, what can I do now to make it out of this". It's an attitude and approach worth cultivating.

In the 60's I was in the Air Force and worked on the ANFS/Q7 computer in Oregon. I rarely worked during the day and usually worked the 4pm to midnght shift. Days for computer maintenance were quiet unless the computer went down (which it often did). So it was common to get official visitors and we would be asked to give them a tour of the blockhouse. The visitors could be a congressman a professor from a local college, a wife of a dignitory or a few school kids. I could to the tour in my sleep and recited all the facts and statistics that were sure to impress. On one tour the visitor was looking over the shoulder of a weapons officer at the computer display and it was 4 pm and the SR-71 was flying from Alaska to land at McClellan fresh off it's trip over Russia and China. No data was displayed just the raw radar dots which were about 3/8ths of an inch apart on his screen. The visitor listened to the operators explanation of what was on the screen and what he was doing and then asked "so what is this" pointing at the string of radar returns that was about 3 inches long. The operator didn't miss a beat and responded that's one of those things we don't talk about. We of course all knew it was an SR-71 and would look for them at the expected time but I had never been asked and I'm not sure what I would have said if I had answered.One of the most exciting things abut that job was making real time repairs of the mainframe. We had two computers and one was active air defense and one was inactive backup. We could switch the two computers in about 30 seconds if we had to but we were required to make the switch in less then two minutes or the system was declared to be "down". What that meant to the maintenance weenie was you had 1 minute and 29 seconds to play with. Typically when the mainframe went down it would begin an automatic resart and I would quickly stand in front of the console and watch the lights. Every light had a meanng and after watching enough normal opperation and restarts you knew what was supposed to happen. What you were lokking for was a light that stayed on or didn't go out or was on or off at inappropriate times. When you found the light it was either that you knew (or thought you knew) what was wrong OR that you now had a clue but still didn't know. If you knew you ran out on the floor grabbed a spare plugable unit and went to the cabinet with thefaulty circuit and replaced it hot. Then back to the console and push restart. You could tell in about 20 seconds if you fixed it. If not while you were dicking around the backup computer had booted up and was receiving radar and other inputs and it was a matter of just pushing a button to switch them. I have done this with my boss glaring at me from behind a desk, with a general standing there demanding to know what was wrong and every other tense combination you can imagine. If you were right you were a "hero" of sorts but if you were wrong you were "shit". My boss was not a nice guy and totally lacked diplomatic skills so it took some balls to do this. But there was kind of a "god" complex we Central computer guys got after awhile and we oozed confidence probably far more then we should have. Basically after a year of tech school followed by a year of OJT and having pulled every plugable unit out there and repaired every circuit spent hours and hours reading logic diagrams we knew the computer intimately so our confidence was not totally misplaced.

I would not believe your friend for back seating it in a Habu. I was a Crew Chief of a Q model tanker refueling the SR-71 out of Okinawa from 77-80. You don't get to fly unless you're a VIP like a general or senator or high up like that.

My brother was a test pilot, after an Air Force career in F-104s and F-4s. He ended up being an Air Force test pilot for the F-16. After being told that he had flown too much and would be sent to a desk job, he retired and became an F-16 test pilot for General Dynamics.

He was a good example of that attitude you mentioned - unflappable, no matter how much the crap around him was falling apart, he simply and quietly focused on solving the problem. A national TV special on daredevils included a piece on him that coincidentally was filmed when his aircraft at Edwards developed an in-flight emergency (the generator cratered, IIRC). The news crew recorded the tense situation at ground control as he calmly ticked off the steps he was taking to bring the aircraft back to a landing - not what would be assumed to be a foregone conclusion. All in a day's work.

A second hand story but kind of illustrates the flip side of being to heroic or unflapable. A friend was in the control tower at Malmstrom AFB when a pilot took off in a plane that had just undergone some maintenance. The plane quicly developed a problem and the discussion became very frantic with the ATC telling the pilot to eject. The pilot kept insisting he could get it under control to the very end but just before the crash the pilots last words were "oh shit".

In 1962 I was assigned to Beale AFB working in the SAGE center. We had no idea of what was going on at the Aribase outside the "blockhouse". One day we were pulled into a meeting room and given a secret briefing on the testing of thew YF12A/ SR71. Its flight capabilities and charcteristics were briefly explained and we were given just enough to know we were to ignore it when it came onto our scopes. It was intereating to watch the blips race across the scope while other (high speed) A/C lumbered along at a leisurely pace. Several years later I was stationed at Kadena and while driving along the runway with my wife I saw the "Blackbird" taxi out and blast off into the sky. I knew exactly what it was from the briefings we had at Beale. I was always proud of the tiny role we played when the SR71 came to be. I had the honor to touch one up close at the Museum in McMinville, Oregon near where I lived in retirement. I love reading the stories of that bird.

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Retired radio engineer, follower of Christ, RF designer, mentor. Radio ham, home shop machinist, lapidary, silversmith, roadie cyclist, learning to be a rifleman, and home defender, - a guy with too many interests to keep track of.

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